The goal of this paper was to investigate the application of the LDPC codes in Digital image watermarking. Based on the analysis of the equivalent channel in the digital watermarking system

a watermarking technique for digital image on the basis of LDPC code is proposed. The algorithm embeds and retrieves the watermark signature into and out of the static image by employing the LDPC code technology and the human visual characteristics. The results demonstrate that the proposed technique has greatly decreased the error code rate of the retrieved watermark and improved the robustness and invisibility.